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Posted to user@karaf.apache.org by Gareth <ga...@gmail.com> on 2011/07/20 04:36:25 UTC
Cellar And Hazelcast Questions
Hello,
I would like to use Karaf as well as Cellar. I also would like to use
Hazelcast for my program (since it is now getting a lot of Apache
integration vs. other open-source clustering software). So I have some
questions:
(1) Is there an issue if I piggyback on the Cellar Hazelcast cluster, or
should I make a completely separate one? Just as a note, I am seeing some
exceptions when I uninstall my bundles after using Hazelcast:
java.lang.ClassNotFoundException:<my class> not found from bundle
[org.apache.karaf.cellar.hazelcast]
at
org.springframework.osgi.util.BundleDelegatingClassLoader.findClass(BundleDelegatingClassLoader.java:103)
at
org.springframework.osgi.util.BundleDelegatingClassLoader.loadClass(BundleDelegatingClassLoader.java:156)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
.
.
Caused by: java.lang.ClassNotFoundException: <My class> not found by
org.apache.karaf.cellar.hazelcast [141]
at
org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:787)
at org.apache.felix.framework.ModuleImpl.access$400(ModuleImpl.java:71)
at
org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1768)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at
org.apache.felix.framework.ModuleImpl.getClassByDelegation(ModuleImpl.java:645)
(2) I see there is an OSGi classloader problem with the Hazelcast Cluster
Monitor. If you use any custom classes in an IMap it cannot find them. e.g.:
Caused by: java.lang.ClassNotFoundException:
org.apache.karaf.cellar.core.Group not found by com.hazelcast.monitor [143]
at
org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:787)
at org.apache.felix.framework.ModuleImpl.access$400(ModuleImpl.java:71)
at
org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1768)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)[:1.6.0_26]
Is there any way around this? Is using the Hazelcast cluster monitor to be
avoided for OSGi/Keraf Cellar?
thanks in advance,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Hello Ioannis,
I found where the issue occurs. It occurs when I try and execute a predicate
on a class I defined. Here is the sample code I used to reproduce the
problem:
My custom class:
public class PredTester implements DataSerializable {
private static final long serialVersionUID = -1359492685240522455L;
private String myvalue;
public PredTester(String value) {
this.myvalue = value;
}
@Override
public void writeData(DataOutput out) throws IOException {
out.writeUTF(myvalue);
}
public String getMyvalue() {
return this.myvalue;
}
@Override
public void readData(DataInput in) throws IOException {
this.myvalue = in.readUTF();
}
}
My activator:
public class Activator implements BundleActivator {
private volatile HazelcastInstance instance = null;
private volatile Thread myThread = null;
private volatile IMap<String,PredTester> myMap = null;
@Override
public void start(BundleContext context) throws Exception {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
ServiceReference reference =
context.getServiceReference("com.hazelcast.core.HazelcastInstance");
instance = (HazelcastInstance) context.getService(reference);
context.ungetService(reference);
try {
myMap = instance.getMap("fred-osgi");
myMap.addIndex("myvalue", true);
myMap.put("test1", new PredTester("belt"));
EntryObject e = new PredicateBuilder().getEntryObject();
@SuppressWarnings("unchecked")
Predicate<String,PredTester> predicate =
e.get("myvalue").equal("belt");
Set<Map.Entry<String,PredTester>> entrySet =
myMap.entrySet(predicate);
logger.info("Entries returned = {}",entrySet.size()); << I believe it
fails here
} catch (Exception ex) {
ex.printStackTrace();
}
Thread.currentThread().setContextClassLoader(classLoader);
}
The following exception is thrown, whether I use an index or not (I thought
using an index may stop Hazelcast needing to deserialize to check for a
match):
21:01:16,037 | ERROR | .cached.thread-1 | AbstractSerializer |
dardLoggerFactory$StandardLogger 58 | - - | Problem reading
DataSerializable class : PredTester, exception:
java.lang.ClassNotFoundException: PredTester not found from bundle
[org.apache.karaf.cellar.hazelcast]
java.io.IOException: Problem reading DataSerializable class :
com.antennasoftware.hazelcasttest.PredTester, exception:
java.lang.ClassNotFoundException:
com.antennasoftware.hazelcasttest.PredTester not found from bundle
[org.apache.karaf.cellar.hazelcast]
at
com.hazelcast.nio.Serializer$DataSerializer.read(Serializer.java:98)[135:hazelcast:1.9.3]
at
com.hazelcast.nio.Serializer$DataSerializer.read(Serializer.java:69)[135:hazelcast:1.9.3]
at
com.hazelcast.nio.AbstractSerializer.toObject(AbstractSerializer.java:105)[135:hazelcast:1.9.3]
at
com.hazelcast.nio.AbstractSerializer.toObject(AbstractSerializer.java:135)[135:hazelcast:1.9.3]
at
com.hazelcast.nio.Serializer.readObject(Serializer.java:62)[135:hazelcast:1.9.3]
at
com.hazelcast.impl.ThreadContext.toObject(ThreadContext.java:113)[135:hazelcast:1.9.3]
at com.hazelcast.nio.IOUtil.toObject(IOUtil.java:149)[135:hazelcast:1.9.3]
at com.hazelcast.impl.Record.getValue(Record.java:143)[135:hazelcast:1.9.3]
at
com.hazelcast.query.Predicates$GetExpressionImpl.doGetValue(Predicates.java:842)[135:hazelcast:1.9.3]
at
com.hazelcast.query.Predicates$GetExpressionImpl.getValue(Predicates.java:836)[135:hazelcast:1.9.3]
at
com.hazelcast.query.Predicates$EqualPredicate.apply(Predicates.java:450)[135:hazelcast:1.9.3]
at
com.hazelcast.query.PredicateBuilder.apply(PredicateBuilder.java:32)[135:hazelcast:1.9.3]
at
com.hazelcast.impl.ConcurrentMapManager$QueryOperationHandler.createResultPairs(ConcurrentMapManager.java:2658)[135:hazelcast:1.9.3]
at
com.hazelcast.impl.ConcurrentMapManager$QueryOperationHandler$QueryTask.run(ConcurrentMapManager.java:2627)[135:hazelcast:1.9.3]
at
com.hazelcast.impl.executor.ParallelExecutorService$ParallelExecutorImpl$ExecutionSegment.run(ParallelExecutorService.java:179)[135:hazelcast:1.9.3]
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)[:1.6.0_26]
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)[:1.6.0_26]
at java.lang.Thread.run(Thread.java:680)[:1.6.0_26]
I guess this makes it difficult to use Hazelcast predicates in OSGi (for
now).
thanks again,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
Ok, I managed to reproduced it. I couldn't reproduce it so far because my
sample bundle was dynamically imported by cellar-hazelcast bundle.
I created a jira issue for that:
https://issues.apache.org/jira/browse/KARAF-842 and I will start working on
it. Till then you can either use a fragment or your own Hazelcast instance.
Thanks Gareth for bringing this up and having the patience to try different
scenarios/combinations.
--
*Ioannis Canellos*
*
http://iocanel.blogspot.com
Apache Karaf <http://karaf.apache.org/> Committer & PMC
Apache ServiceMix <http://servicemix.apache.org/> Committer
Apache Gora <http://incubator.apache.org/gora/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
Hi Gareth,
I think that it doesn't matter who initializes the instance. It matters
though who creates the Hazelcast collection (Set,List,Map etc).
So I think that the best approach is to reuse cellar's hazelcast instance
which is exported as a service.
I really don't understand why these scenarios fail for you. I reused the
code you posted in your previous example and it worked fine (that was
scenario 1).
I've created a sample of a hazelcast application that reuses the cellar
hazelcast instance (imports it as an OSGi service). You can have a look of
that sample at:
https://svn.apache.org/repos/asf/karaf/cellar/trunk/samples/hazelcast-app/.
I wonder if the reason that makes this sample work is the fact that
cellar-hazelcast has a dynamic-import on org.apache.karaf.cellar.* packages.
I will try changing the package name and see if it still works.
--
*Ioannis Canellos*
*
http://iocanel.blogspot.com
Apache Karaf <http://karaf.apache.org/> Committer & PMC
Apache ServiceMix <http://servicemix.apache.org/> Committer
Apache Gora <http://incubator.apache.org/gora/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Hello Ioannis,
Thank you very much for all your responses. It has been very helpful.
Please bear with me. I must be missing something fundamental here.
I realize there are two variables in play here rather than one (i.e. who
initializes the Hazelcast instance, whether the TCCL is used). I don't
believe Hazelcast can inherit my TCCL if my bundle only uses Hazelcast as a
service, can it? When you ran your test, was the Hazelcast instance
initialized as part of the same bundle?
I did run through a few scenarios to confirm my understanding:
(1) Use existing Karaf Hazelcast instance, use TCCL - FAILED
(2) Create my own Hazelcast instance, don't use TCCL - FAILED
(3) Create my own Hazelcast instance, use TCCL - SUCCESS!
So it appears that unless I create my own Hazelcast instance, Hazelcast
cannot see my classes (unless I use fragments, of course). Have I missed
something obvious here?
Would it be an idea to get cellar to use my hazelcast instance? Thus in my
bundle which starts hazelcast, I could make sure I import both cellar and my
own packages. Thus hazelcast can load both cellar and my classes via the
TCCL. Would that make sense?
Thank you very much again for all your help.
regards,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
Hi Gareth,
I created a sample project based on the code you pasted in your previous
email and it works fine for me.
The only modification I did was was to create the default constructor on the
PredTester class, but this is something that I don't think thats directly
related to the problem you encountered.
As I mentioned in my previous post as long as you set the thread context
class loader everything should work fine. Now regardin your question about
fragments. I think that using fragments would also work, but they have the
drawback that you have to install the prior to hazelcast or refresh the
hazelcast bundle afterwards.
--
*Ioannis Canellos*
*
http://iocanel.blogspot.com
Apache Karaf <http://karaf.apache.org/> Committer & PMC
Apache ServiceMix <http://servicemix.apache.org/> Committer
Apache Gora <http://incubator.apache.org/gora/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Hello Ioannis,
I was wondering. Would using fragments be a reasonable way to solve
Hazelcast classloading issues (i.e. any class which may need to be
serialized/deserialized by Hazelcast, I should include in a fragment which
is attached to the Hazelcast bundle)?
thanks in advance,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
I think that there are two types of problems:
a) The one is that hazelcast-monitor doesn't see cellar classes. This has to
be fixed on the Hazelcast side (I will try to work on a patch).
b) When you reuse the Hazelcast instance, that is exported by
cellar-hazelcast bundle, you get exception when custom classes get
deserialized. For this case an example would help.
--
*Ioannis Canellos*
*
http://iocanel.blogspot.com
Apache Karaf <http://karaf.apache.org/> Committer & PMC
Apache ServiceMix <http://servicemix.apache.org/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Hello Ioannis,
You need the sample to reproduce this exception (you answered my question
about hazelcast classloading in the hazelcast forums)?:
java.lang.ClassNotFoundException:<my class> not found from bundle
[org.apache.karaf.cellar.hazelcast]
Give me a little while to create a simplified program.
thanks again,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
Could you sent me a small sample?
--
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*
http://iocanel.blogspot.com
Apache Karaf <http://karaf.apache.org/> Committer & PMC
Apache ServiceMix <http://servicemix.apache.org/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Thankyou again for the response.
I was already doing the classloader switch in some threads as I do load jndi
properties files. I added the classloader switch to any other thread which
accesses Hazelcast. I didn't notice a difference. Should all the issues have
been fixed by this change?
Could I perhaps fix my problem using fragments? If I created a fragment with
the problematic classes, and made the Fragment-Host the hazelcast bundle,
would that be a possible workaround?
thanks in advance,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Ioannis Canellos <io...@gmail.com>.
Hi Gareth,
Hazelcast is using Thread.getCurrentThread().getContextClassLoader() in
order to read object it exchanges over the cluster.
You may have to to change the context class loader before you create the
Map.
For example:
ClassLoader originalClassLoader =
Thread.currentThread().getContextClassLoader();
try {
Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
//Do stuff here.
} finally {
Thread.currentThread().setContextClassLoader(originalClassLoader);
}
I know its not the most elegant thing to do, but it will get things
working.
--
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*
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Apache ServiceMix <http://servicemix.apache.org/> Committer
*
Re: Cellar And Hazelcast Questions
Posted by Gareth <ga...@gmail.com>.
Hello JB,
Thank you very much for responding so quickly!
I am just using the default cluster group (only one machine currently as I
am testing on my Mac):
karaf@root> cluster:group-list
Node Group
* 192.168.190.1:5701 default
I am getting the HazelcastInstance via the service cellar creates (directly
now as I am still exploring OSGi, probably using blueprint in the future):
ServiceReference reference =
bundleContext.getServiceReference("com.hazelcast.core.HazelcastInstance");
HazelcastInstance instance = (HazelcastInstance)
bundleContext.getService(reference);
bundleContext.ungetService(reference);
Then I am looking up/creating two maps (MyKeyType and MyValueType are
defined in the same bundle -> the exception thrown below is for MyKeyType):
IMap<String,Long> myMap1 = hazelcastInstance.getMap("myMap1");
IMap<MyKeyType,MyValueType> myMap2 =
hazelcastInstance.getMap("myMap2");
Is that enough information? Am I doing anything I shouldn't be doing?
thanks in advance,
Gareth
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Re: Cellar And Hazelcast Questions
Posted by Jean-Baptiste Onofré <jb...@nanthrax.net>.
Hi Gareth,
thanks for your interest in Karaf and Cellar.
It seems that you found a bug. I'm gonna raise a Jira and reproduce your
issue with a test case.
Could you provide some information about your bundle ?
Do you have create Cellar group ?
Thanks
Regards
JB
On 07/20/2011 04:36 AM, Gareth wrote:
> Hello,
>
> I would like to use Karaf as well as Cellar. I also would like to use
> Hazelcast for my program (since it is now getting a lot of Apache
> integration vs. other open-source clustering software). So I have some
> questions:
>
> (1) Is there an issue if I piggyback on the Cellar Hazelcast cluster, or
> should I make a completely separate one? Just as a note, I am seeing some
> exceptions when I uninstall my bundles after using Hazelcast:
>
> java.lang.ClassNotFoundException:<my class> not found from bundle
> [org.apache.karaf.cellar.hazelcast]
> at
> org.springframework.osgi.util.BundleDelegatingClassLoader.findClass(BundleDelegatingClassLoader.java:103)
> at
> org.springframework.osgi.util.BundleDelegatingClassLoader.loadClass(BundleDelegatingClassLoader.java:156)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
> at java.lang.Class.forName0(Native Method)
> at java.lang.Class.forName(Class.java:247)
> .
> .
>
> Caused by: java.lang.ClassNotFoundException:<My class> not found by
> org.apache.karaf.cellar.hazelcast [141]
> at
> org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:787)
> at org.apache.felix.framework.ModuleImpl.access$400(ModuleImpl.java:71)
> at
> org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1768)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
> at
> org.apache.felix.framework.ModuleImpl.getClassByDelegation(ModuleImpl.java:645)
>
> (2) I see there is an OSGi classloader problem with the Hazelcast Cluster
> Monitor. If you use any custom classes in an IMap it cannot find them. e.g.:
>
> Caused by: java.lang.ClassNotFoundException:
> org.apache.karaf.cellar.core.Group not found by com.hazelcast.monitor [143]
> at
> org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:787)
> at org.apache.felix.framework.ModuleImpl.access$400(ModuleImpl.java:71)
> at
> org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1768)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)[:1.6.0_26]
>
> Is there any way around this? Is using the Hazelcast cluster monitor to be
> avoided for OSGi/Keraf Cellar?
>
> thanks in advance,
> Gareth
>
>
>
>
>
>
> --
> View this message in context: http://karaf.922171.n3.nabble.com/Cellar-And-Hazelcast-Questions-tp3184320p3184320.html
> Sent from the Karaf - User mailing list archive at Nabble.com.
--
Jean-Baptiste Onofré
jbonofre@apache.org
http://blog.nanthrax.net
Talend - http://www.talend.com